once you figured out saclng Q or checking was not the right line,if you saced Rd7...BxRd7,was able to see 2.Qd6+...Kf7, 3.Qd7+...Kf8, 4.Ne6#.Nice puzzle,white's pawn's played a big part keeping K from escaping,especialy,pawn on h7.Thank's Chess. Com,good day chess head's

The Black Bishop was a thorn in White's side, and somehow White needed to get his Knight onto the square where the Queen was standing without losing any tempo.

The Rook sacrifice was a nice move to get the Black Bishop into a position where White could capture it. But even better was the second move by White which delayed the capture of the Bishop by one move. That way, when the Bishop was eventually captured on the third move, Black would be forced to move his King to safety.

If White had have captured the Bishop on the second move, then Black would have had the tempo to create an escape route for the King. This puzzle demonstrates the strategy of "patience".

Good annalogy,nice to hear from you,I saced R to get Qd6 check on second move,from there could see mate by 3.QxBd7+...Kf8, 4.Ne6#.pawn's kept K from escaping,and made mate possible